The Gnarly Head Old Vine Zinfandel is made from grapes grown on vines that are between 35 and 80 years of age. The output from older vines is reduced, which explains the intense, concentration of berry and spice aromas. The grapes are harvested by hand before being gently pressed in the domain's cellar. Fermentation lasts between 7 to 9 days. The wine is aged in French, American and Hungarianoak barrels, which gives the wine its notes of vanilla and chocolate.